Answer:
An increase in the number of snakes
Explanation:
From the food web, the only way for frog population to increase is:
1) increase of cricket population. (increased food source)
2)decrease of hawks population (less predator)
An increase in snake population will result in mice population to fall as more snakes will hunt and feed on the mice. This causes lesser mice to feed on grasses. Resulting in increased food for crickets. As time passes, due to sufficient food, cricket population will increase which in turn increases the amount of food available for frogs to eat.
Assuming the number of predators remain constant and amount of crickets (food) increases, more frogs will survive to maturity and reproduce, causing the amount of frogs to increase.
